A study of Li-rich stars discovered by ROSAT in Taurus-Auriga

In recent years, large numbers of lithium-rich stars were discovered near several nearby star forming regions (SFRs). We present a detailed study of those stars discovered in and near the central region of the Taurus-Auriga T Tauri association, based on high-resolution echelle spectroscopy and proper motion data. We find that about 60 per cent of our sample can be regarded as pre-main sequence (PMS) stars, while the remaining stars likely are foreground zero-age main sequence (ZAMS) stars. We conclude that the PMS stars are likely associated with the Taurus-Auriga SFR, while the ZAMS stars may represent a population of somewhat older Gould Belt stars. The fraction of ZAMS stars in the Taurus-Auriga sample studied in this work is larger than in a similar sample in the Lupus SFR, and we argue that this may be explained by the spatial structure of the Gould Belt and the Sun’s location within it.